1. Field of Invention
The present invention relates to an apparatus for stacking folded paper sheets in which the collecting device is stationary during the sheet collecting operation.
2. Background Information
Duplex printed sheets are often bound into finished documents, such as booklets, by a paper-handling accessory. Machines perform finishing operations, such as binding, folding, trimming, saddle stapling, and hole drilling. The handling of sheets of paper for booklet making includes additional manipulating operations such as collecting and positioning sheets of paper. Booklet making systems can operate to collect folded sheets on a workpiece by rotating the workpiece to place the two portions of the folded sheet on opposite sides of the workpiece.
For example, a system for finishing printed sheets into booklets is described in U.S. Pat. No. 6,099,225 (Allen et al.), hereby incorporated by reference in its entirety. The ""225 patent discloses an inverted V-shaped workpiece for collecting folded booklet sheets.
A system for making saddle-stitched booklets on a sheet-wise basis is disclosed in PCT No. WO 00/18583 (Trovinger et al.), hereby incorporated by reference in its entirety. In this system, folded booklet sheets are forwarded from a folding device to a reciprocating saddle with the use of a secondary drive system. The reciprocating saddle is described as permitting a trailing side of a folded sheet to be transported onto the backside of the saddle.
U.S. patent application Ser. No. 10/084,459, filed Feb. 28, 2002, entitled xe2x80x9cSYSTEM FOR HANDLING FOLDED SHEET MATERIALxe2x80x9d (Attorney Docket No. 10015158-1) (Trovinger), hereby incorporated by reference in its entirety, discloses a system for moving folded sheets to a collecting device and clamping the folded sheets against the collecting device. The folded sheets are moved to the collecting device in a non-linear path, where each sheet is delivered to the collecting device such that a leading side and a trailing side of the sheet are respectively delivered to different sides of the collecting device.
U.S. patent application Ser. No. 10/084,460, filed Feb. 28, 2002, entitled xe2x80x9cBOOKLET MAKERxe2x80x9d (Attorney Docket No. 10014012-1) (Trovinger), hereby incorporated by reference in its entirety, discloses a booklet maker including a pivotable collecting device. The pivotable collecting device has two supporting sides formed with a saddle shape, and a rotatable transferring device including a displaceable clamping component. The transferring device delivers a folded sheet material to the collecting device along a non-linear path, and the collecting device pivots to receive the folded sheet material from the transferring device such that different portions of the folded sheet material are supported by different sides of the two supporting sides of the collecting device.
U.S. patent application Ser. No. 10/084,462, filed Feb. 28, 2002, entitled xe2x80x9cPIVOTABLE COLLECTING DEVICExe2x80x9d (Attorney Docket No. 10015154-1) (Trovinger), hereby incorporated by reference in its entirety, also discloses a pivotable collecting device for handling a folded sheet material.
The present invention is directed to an apparatus for stacking a folded paper sheet. In an exemplary embodiment, an apparatus for stacking a folded paper sheet comprises a collecting device having a first side and a second side, a first sheet drive assembly including a first sheet contacting component, the first sheet drive assembly located on the first side of the collecting device and operable to move between a sheet receiving position and a sheet discharging position, and a second sheet drive assembly including a second sheet contacting component, the second sheet drive assembly located on the second side of the collecting device and the second sheet contacting component translates to pinch the sheet on the second side of the collecting device. The collecting device is stationary with respect to at least one of a paper path, the first sheet drive assembly and the second sheet drive assembly during a sheet collecting operation.
A booklet making system according to exemplary embodiments comprises a paper path, a paper folding apparatus, and an apparatus for stacking a folded paper sheet during a sheet stacking operation. The apparatus includes a collecting device having a first side and a second side, a first sheet drive assembly including a first sheet contacting component, located on the first side of the collecting device and operable to move between a sheet receiving position and a sheet discharging position, and a second sheet drive assembly located on the second side of the collecting device including a second sheet contacting component translatable to pinch the sheet on the second side of the collecting device. The collecting device is stationary with respect to at least one of the paper path, the first sheet contacting component and the second sheet contacting component during a sheet collecting operation.
In an exemplary embodiment, a folded sheet handling apparatus can include a collecting device having a first side and a second side, means for guiding a folded sheet from a paper path to the collecting device such that a leading portion of the folded sheet is positioned on the collecting device, means for moving a folded sheet along at least one of the first side and the second side of the collecting device, and means for positioning a trailing edge portion of the folded sheet on the collecting device. The collecting device is stationary with respect to the paper path during a sheet collecting operation.
An exemplary method for handling folded paper sheets, comprises guiding a first portion of a folded paper sheet to a first side of a collecting device along a paper path which includes a first sheet contacting component of a first sheet drive assembly, contacting the first portion of the folded paper sheet with a second sheet contacting component of a second sheet drive assembly, contacting a second portion of the folded paper sheet with the first sheet contacting component of the first sheet drive assembly, rotating or translating at least one of the first sheet contacting component and the second sheet contacting component in a sheet advancing direction to advance the first portion of the folded paper sheet along the first side of the collecting device, repositioning the first sheet drive assembly to guide the second portion of the folded paper sheet to a second side of the collecting device, and rotating or translating at least one of the first sheet contacting component and the second sheet contacting component in a sheet reversing direction to position the second portion of the folded paper sheet along the second side of the collecting device.
Another exemplary method for handling folded paper sheets comprises guiding a leading portion of a first folded paper sheet to a second side of a collecting device, guiding the leading portion of the first folded paper sheet between a sheet contacting component and the second side of the collecting device, positioning a fold in the first folded paper sheet over an edge of the collecting device, moving the sheet contacting component to apply a force against the second side of the collecting device to hold the leading portion of the first folded paper sheet stationary, and sweeping at least one sweep element from a first position on a first side of a paper path, through the paper path, to a second position so as to position a trailing portion of the first folded sheet along the first side of the collecting device.